The United States consumes approximately 30% of the world's annual energy supplies. About 93% of our energy requirements are provided by fossil fuels, of which nearly half are from crude oil sources. Since crude oil production in the United States has been falling off since reaching a peak in 1972-1973, most of our crude oil supplies come largely from the Middle East. Recent events in the Middle East have sharply focused our attention to our overdependence on foreign oil supplies. Thus, until we can develop alternate energy sources, our attention has focused on fuel conservation and reducing our enormous appetite for crude oil.
One of the largest users of crude oil sources in the United States is the automobile. Because of this, heavy consideration is being given to increase the efficiency of fuel usage of internal combustion engines.
Automobiles are generally powered by either one of two types of internal combustion engines, that is, spark ignition or compression ignition. By far the most popular is the spark ignition engine which generally employs a carburetor to atomize and mix the fuel with air flowing into the engine. The carburetor is usually mounted on an intake manifold. The intake manifold distributes the fuel/air mixture produced by the carburetor into the combustion chambers of the engine. The fuel/air mixture from the carburetor is drawn into the combustion chambers of the engine by a vacuum created in the intake manifold by reciprocating movement of the pistons during the "suction stroke" of each cylinder of the internal combustion engine.
In a typical V-8 engine there are eight passages in the intake manifold which connect a plenum chamber formed at the inlet of the intake manifold and located below the carburetor, into each of the eight cylinders of the internal combustion engine. In each of the cylinders of the internal combustion engine, the fuel/air mixture from the carburetor is then compressed, ignited by means of a spark plug and the resulting combustion of the fuel/air mixture creates "a power stroke" on the piston. The power stroke on the piston causes the crankshaft to receive a power force which is then transmitted mechanically to the wheels of the vehicle.
One major problem with carbureted internal combustion engines is that a carburetor produces a mixture of air and vaporized fuel, atomized fuel, and liquid fuel. This, in turn, makes it difficult, if not impossible, to provide a uniform fuel/air mixture through the intake manifold into each of the cylinders of the internal combustion engine. For example, the atomized fuel, consisting of very fine particles of fuel suspended in air, has a tendency to come out of suspension when the fuel/air mixture goes through the turns in the passages of the intake manifold. Liquid fuel, which is not suspended in the air, travels along the walls of the passages of the intake manifold toward the inlet port of the cylinder. This non-uniform fuel/air mixture produces a "rich" fuel/air mixture for some of the cylinders of the engine and causes at least one or more of the cylinders to have a "lean" fuel/air mixture. To provide satisfactory engine performance, the usual practice is to richen up the overall fuel/air mixture from the carburetor so as to richen up the "lean" cylinders. This practice, of course, increases the fuel consumption of the internal combustion engine.
There are several known devices intended to provide improved fuel economy for internal combustion engines. In U.S. Pat. No. 3,943,900 issued Mar. 16, 1976 to Ulysses Lee Primrose, a generally thin and flat plate like member having appropriate passages so as to enable it to be bolted to an intake manifold below a carburetor is disclosed. Air is injected at a point within the intake manifold to enable the mixture of air injected there at to disperse in the manifold air stream. The air which is injected into the manifold then is mixed with the fuel/air mixture from the carburetor and provides a leaning of the overall fuel/air mixture to the internal combustion engine. This device is complex and does not concentrate the fuel/air mixture toward the combustion chambers of the engine.
Alfred E. Scott, in U.S. Pat. No. 3,998,195, issued on Dec. 21, 1976, discloses a flow control and vaporizing chamber which is positioned between the carburetor and the intake manifold. The chamber includes a cylindrical member containing a plurality of closely spaced, longitudinally extending tubes. The longitudinally extending tubes receive the fuel/air mixture from the carburetor so as to break up the fuel in the mixture and vaporize the fuel and direct the mixture to the cylinders of the engine. This device thus serves to break down the raw fuel into minute particles thereby further atomizing the fuel droplets. This device is also complex and does not concentrate the fuel/air mixture.
In U.S. Pat. No. 4,078,532, issued to Joseph A. Smith on Mar. 14, 1978, a device adapted to be placed between the carburetor and the intake manifold is disclosed. The device includes a plate member having a plurality of spaced apertures for treating the fuel/air mixture from the carburetor so as to substantially vaporize the fuel prior to entry of the fuel into the intake manifold for distribution to the combustion chambers of the engine. This device is again complex and does not concentrate the fuel/air mixture toward the combustion chambers of the engine.
Stephens, in U.S. Pat. No. 3,966,430, issued June 29, 1976, also discloses a fuel economizer device which is inserted between the carburetor and intake manifold of an internal combustion engine. This device utilizes one or more solid conical members having a series of axial and semi-radially directed apertures. The fuel/air mixture leaving the carburetor is forced into the apertures in the conical member so as to increase the turbulence and homogenization of the fuel/air mixture before being introduced into the engine. This device is, however, complex and expensive to fabricate and does not concentrate the fuel/air mixture toward the combustion chamber of the engine.
Another fuel economizer device is disclosed in U.S. Pat. No. 4,109,620, to George M. Weff, issued on Aug. 29, 1978. This fuel economizer device is adapted for mounting within the throat of an intake passageway of a conventional intake manifold. This fuel economizer device includes a cylindrical sleeve and an annular lip at the top of the sleeve to engage the top of the intake manifold. The device is sandwiched between the intake manifold and a conventional carburetor. The device is also formed with an elliptical shaped deflector partition to deflect fuel/air mixture from the carburetor to the intake manifold. This device, however, does not seek to enhance the fuel/air mixture from the carburetor nor does it concentrate the fuel/air mixture to a point near the intake valve. Therefore, this device has not been found to be widely used in practice.
Finally, U.S. Pat. No. 4,123,996, issued Nov. 7, 1978 to Gillbrand et al, discloses a complex scheme for injecting fuel into the intake manifold of an internal combustion engine. This device controls both the time in which the fuel/air mixture is ignited and the volume of the fuel/air mixture drawn into the engine. The volume of the fuel/air mixture drawn is regulated by a fixed constriction in the inlet passage of the engine. The fuel is injected into the inlet passage by fuel injection valves in response to a control system. This device is not suitable for use with engines fitted with carburetors and is expensive and complicated to make.
None of the aforementioned devices concentrates the fuel/air mixture from the carburetor to a point adjacent but spaced away from the intake valve for each cylinder of the engine in order to provide improved fuel economy for spark ignition engine. In addition, none of the aforementioned devices have been widely used in practice or are simple and inexpensive to make and install in the engine.